<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .div1{
            width: 100px;
            height: 100px;
            background: red;
            color: white;
            text-align: center;
            line-height: 100px;
            font-size: 30px;
            border-radius: 10px;
            margin: 200px auto 10px;
        }
        .div2{
            width: 100px;
            height: 100px;
            margin: 0 auto;
            text-align: center;
        }
    </style>
</head>
<body>

        <div class="div1" id="div1">
            <b>未开始</b>
        </div>
        <div class="div2">
            <button onclick="getname()">点名</button>
        </div>

        <script>

            function getname() {

                var divNode = document.getElementById("div1")

                // divNode.replaceChild(document.createTextNode("zs"),  divNode.childNodes[0])
                // divNode.innerText = "zs"
                // divNode.innerHTML = "zs"

                // divNode.innerText = "<b>zs</b>"
                divNode.innerHTML = "<b>zs</b>"


            }

        </script>
</body>
</html>
